An increasing number of wells have been completed with the installation of liners, perforated or slotted liners, screens, and/or gravel packing. These configurations are typically connected to smaller-diameter production tubing extending to the surface. For example, an installation having a 7-inch liner or base pipe of a screen could be connected to 3½ inch production tubing or and installation where an expandable screen or base pipe has been installed and expanded.
Maintaining and completing these installations can require a variety of localized processes, for example, acid washes for screens and gravel packs, water shut-off water polymer injection through perforations, screens and gravel packs, open hole and through casing perforation stimulation. The efficiency of these processes is dependent on the proper placement and direction of the treating fluids.
The smaller production tubing limits the size and type of tools and equipment available to service these configurations. Tools generally available from oil tool suppliers called “through-tubing” tools are used to perform these processes. Tools that comprise an injection port located between spaced seal elements to isolate a well section are called Selective Injection Packers. Selective Injection Packers utilize cups or inflatable seal elements that are designed to run through production tubing and isolate a portion of the well to allow precise injection of treatment chemical. While these tools are being used currently, they present isolation and retrieving problems.
Tools with cup-type seal elements have size limitation, and tools with inflatable seal elements must be successfully inflated, utilized and then deflated before moving to a different location. Once inflated, the tool cannot slide longitudinally along the wellbore and, thus, cannot inject fluids while they are being moved. When settable fluids are being injected, the time consumed with inflation-deflation between injections can result in failures. In addition, these inflatable seal tools suffer from the inherent risk of the failure to inflate or deflate.
Thus, there are needs for methods and apparatuses for performing through-tubing isolated injection of treatment fluids into materials in and surrounding wellbores.